Method and apparatus for making tubular members



Oct. 15, 1940.-

H. .1. KLUG METHOD AND APPARATUS FOR MAKING TUBULAR MEMBERS Filed Sept. 15, 1939 3 Sheets-Sheet l 1N VENTOR.

4w ATTORNEYS.

Oct. 15, 1940. H. J KLUG 2,217,985

METHOD AND APPARATUS FOR MAKING TUBULAR MEMBERS Filed Sept. 16,1939 3 Sheets-Sheet 2 INVENTOR. A /w BY A; ATTORNEYS.

Oct. 15, 1940. H. J. KLUG 2,217,985

METHOD AND APPARATUS FOR MAKING TUBULAR MEMBERS Filed Sept. 16. 1939 3 Sheets-Sheet 5 INVENTOR.

I BY W-$5.;

AL. ATTORNEYS.

atented Oct. 15, 1940 ATENT OFFICE METHOD AND APPA TUB I RATUS FOR MAKING MEMBERS corporation of Pennsy lvania Application September 16, 1939, Serial No. 295,234

6 Claims.

This invention relates to methods and apparatus for making tubular members, and, more particularly, is concerned with improved means and methods for forming metal skelp into a tubular body as, for example, in the manufacture of longitudinally welded pipe from preheated skelp.

It is old to heat flat metal skelp in a furnace and thereafter pass the skelp through forming rolls which shape the flat skelp into a tubular body having a longitudinal seam which is welded by welding rolls positioned adjacent to the forming rolls. Further, it is old in the manufacture of longitudinally welded tubing and pipe to shape flat skelp, usually while cold, into a tube by passing the skelp through a large number of consecutively operating bending and forming rolls. However, such plurality of bending and forming rolls are relatively expensive to construct and maintain in operation and this is particularly true where a plurality of sizes of pipes are adapted to be manufactured. Every pipe size requires a different set of bending and forming rolls and these are expensive as well as being difilcult and time-consuming to change for operation on different pipe sizes.

When a single pair of forming rolls is used to bend the fiat skelp into substantially tubular shape I have found that the lateral edges or corners of the sides of the skelp engage with the forming rolls so that the corners of the skelp are rounded off. This results in an objectionably visible seam in the pipe which is due to the fact that the rounded-off corners of the skelp are at the outside of the pipe and are complementary to each other to form a distinct-groove or depression in the pipe even after welding. Further, bending flat skelp into a tubular shape by a single pair of forming rolls of known construction has resulted in scoring of the forming rolls because of the continued application of pressure on the relatively sharp skelp edges.

It is the general object of my invention to avoid and overcome the foregoing and other difilculties of and objections to known methods and apparatus for making tubular members, such as pipe, by the provision of apparatus including a single pair of forming rolls for shaping the fiat skelp to tubular form without the application of pressure on the lateral edges or corners of the skelp.

Another object of my invention is to provide an improvede method for making welded pipe or the like from flat skelp and wherein the skelp is bent into tubular form by the application of substantially oppositely directed pressure applied adjacent to the lateral edges of the skelp but spaced therefrom.

Another and more specific object of my invention is the provision of forming rolls for bending flat skelp to tubular form by the application of 5 pressure adjacent to but spaced from the'lateral edges of the skelp.

The foregoing and other objects of my invention are achieved by the provision of apparatus for making welded pipe and the like, and in- 10 eluding a pair of cooperating forming rolls having working faces which together provide a substantially circular pass, but which are cut away adjacent the points normally engaged by the lateral corners of the skelp so that the working 15 faces of the rolls engage with the skelp adjacent the lateral edges of the skelp but spaced therefrom. My improved apparatus is associated with a skelp-heating furnace and forming and welding rolls. Each of the forming rolls has a sub- 20 stantially semi-circular contour but is relieved over an arc of appproximately 10 at a point substantially from the valley of the rolls.

My new and useful method of making tubular members from fiat skelp and the like contem- 25 plates bending heated skelp into tubular shape by applying a single pair of substantially oppositely directed forces against the skelp adjacent to but spaced from the lateral edges of the skelp.

For a better understanding of my invention 30 reference should be had to the accompanying drawings wherein Fig. 1 is a side elevation partly in section of apparatus incorporating the principles of my invention; Fig. 2 is an enlarged plan view of the forming rolls illustrated in Fig. 1; 35 Fig. 3 is a side elevation of the forming rolls shown in Fig. 2; Fig. 4 is a vertical, transverse, cross sectional view of a single roll as taken on line IV-IV of Fig. 2; Fig. 5 is a view similar to Fig. 4 but illustrating the usual prior art roll Q0 structure; Figs. 6 and "I are views similar to Fig. 4 but illustrating modifications of my invention; Fig. 8 is a transverse cross sectional view through a pipe orother tubular member made by prior art practices and apparatus, and illustrating the 45 relatively deep longitudinal groove adjacent the seam; and Fig. 9 is a view similar to Fig. 8 but illustrates a tube made up in accordance with the principles of my invention.

Although my invention is broadly applicable to various uses in the manufacture of tubular members from skelp and the like, it is particularly beneficial in making longitudinally welded tub ing by the continuous process from preheated skelp. all as disclosed and claimed in detail in Patent Nos. 1,026,103 and 1,476,537. Accordingly, I have illustrated my invention and will describe it as employed in the manufacture of continuously welded tubing.

In the drawings the numeral It) indicates a furnace for receiving and preheating skelp marked S which is usually passed continuously through the furnace as on suitable conveyor means I2. Positioned adjacent the furnace i is a forming, Welding and sizing unit, indicated as a whole by the numeral I4, and including a pair of forming rolls l6 usually mounted upon vertical axes, a pair of welding rolls l8, usually mounted on horizontal axes, and a plurality of pairs of drawing and sizing rolls shown at 20. After leaving the forming and sizing rolls 20 the welded and sized tube marked T may be cut into lengths by a saw 19 and thereafter subjected to descaling or further sizing apparatus indicated at 2|.

The forming rolls I6, shown in detail in Figs. 2, 3 and 4, are formed with substantially semicircular working faces 22 which together form a substantially circular pass for receiving the skelp S. The skelp S, as clearly illustrated in Figs. 2

' to 4 of the drawings, is bent by the forming rolls into a substantially tubular shape as it is moved through the rolls. Usually, the longitudinal seam in the formed tube is positioned at the bottom of the tube so that scale and the like may fall out of the seam prior to welding, and for other reasons which are not of interest so far as the present invention is concerned.

In forming the flat skelp to the substantially tubular shape shown, the edges of the skelp normally engage with the working faces 22 of the rolls it when the rolls are of standard type in the manner particuarly illustrated in Fig. 5. From this view it will be recognized that the forming pressure applied by the rolls to the skelp is directed against the extreme lateral edges or corners of the skelp so that the result is a wearing away or a rolling down of the lateral corners of the skelp edges. This is objectionable for the reason that when the skelp is subsequently welded along the longitudinal seam a longitudinally extending groove 24, formed by the opposed rounded corners of the skelp, is clearly evident on the outside surface of the tubular member, all as illustrated in Fig. 8 of the drawmgs.

In accordance with my present invention, I avoid the application of pressure to the extreme lateral edges or corners of the skelp and instead apply the forming pressure adjacent to the lateral edges of the skelp but spaced therefrom. This type of forming pressure may be obtained in various ways. For example, in the formof my invention illustrated in Fig. 4 I have relieved or cut away the working surface of the roll I6 by the provision of a groove 26. The groove 26 extends over an arc of approximately and is positioned approximately 40 to 50 away from the valley of the working face 22 of the roll I6. From Fig. 4 it will be seen that the working face 22 of the roll engages with the side of the skelp S adjacent to but spaced from the extreme lateral edge of the skelp. The extreme lateral edge of the skelp extends into the groove 26 and does not engage the roll so that there is no rounding or wearing off of the extreme lateral edges or corners of the skelp.

A modified roll construction for achieving the desired objects of my invention is shown in Fig. 6. In this form of the invention the roll indicated at lfia is provided with a working face 2 a which is terminated at a point between about 35 and about 60 from the valley of the working face 22, and usually is terminated at about 45 from the valley of the working face. As shown in Fig. 6, the skelp S is engaged by the working face 221:. at a point adjacent to but spaced from the lateral edges of the skelp.

The modification of my invention shown in Fig. '7 is very similar to that illustrated in Fig. 6. In Fig. 7 the roll i6b is made in two parts, as illustrated, which are separated by a spacer Him. The working face 22b of the complete roll is substantially semi-cylindrical in contour but is interrupted by the groove between the roll parts effected by the spacer l6:c. Like the rolls illustrated in Figs. 4 and 6, that shown in Fig. 7 engages with the skelp S at points adjacent to but spaced from the lateral edges of the skelp.

It is believed that the improved method and apparatus of my invention will be completely understood from the foregoing description. However, briefiy reviewing the operationit will be understood that in making tubular members, such as longitudinally welded pipe, the flat skelp S is passed through the heating furnace i0 and is brought to substantially welding temperature. Thereafter, the skelp is passed through the forming rolls [6 and because of the shape of the rolls is bent in a single operation to substantially a tubular shape, but without deforming the lateral edges of the skelp. The tubular member formed by the forming rolls is passed to the welding rolls and to the final sizing and forming rolls 20. A longitudinally welded pipe or other tubular member constructed in accordance with the method of and by the apparatus of my invention is illustrated in Fig. 9 of the drawings. From this figure it will be recognized that the longitudinal seam in the pipe is characterized by a smooth flush exterior which makes it very diflicult to see the seam in the finished product.

Fom the foregoing it will be recognized that the objects of my invention have been achieved by the provision of relatively inexpensive apparatus and improved methods for quickly and accurately forming flat skelp in the manufacture of longitudinally welded pipe and the like, and that the objections to and difiiculties of prior art practices have been avoided and overcome.

Although I have specifically illustrated and described several particular embodiments of my invention, and have referred to using only a single pair of forming rolls relieved over an arc of approximately 10 at a point between about 35 and about 60 from the bottom of the roll, it should be understood that many of the advantages of my invention may be retained if two or more pairs of forming rolls constructed in accordance with the principles of my invention are employed. If two or more pairs of forming rolls are used they will be relieved adjacent the corners of the skelp in the manner heretofore described in detail. a In fact, the location and size of the relieved portion of therolls varies with the size of the tubular member being formed even by a single'pair of rolls, and obviously when more than one pair of forming rolls is used the rolls are provided with relieved portions adjacent the skelp edges even though such portions may be outside of the angular limits stated last above.

While in accordance with the patent statutes I have particularly illustrated and described my invention, it should be appreciated that I am not to be limited thereto or thereby but that the scope of my invention is defined in the appended claims.

I claim:

1. In an apparatus for making welded cylindrical tubing from heated flat metal skelp, a pair of cooperating rolls forming a Substantially circular skelp-shaping pass, each roll being provided with a substantially semi-circular pass face whose continuity is interrupted at a point so spaced from the valley of the shaping pass'that the sides of skelp are initially engaged by the rolls solely at points spaced from its edges.

2. In an apparatus for making welded cylindrical tubing from heated flat metal skelp, a pair of cooperating rolls forming a substantially circular skelp-shaping pass, each roll being provided with a substantially semicircular pass face whose continuity is interrupted to form a pocket so spaced from the valley of the shaping pass that the pockets initially receive the edges of the skelp and that the sides of skelp are initially engaged by the rolls solely at points spaced from its edges.

3. In an apparatus for making welded cylindrical tubing from heated flat metal skelp, a pair of cooperating rolls forming a substantially circular skelp-shaping pass, each roll being provided with a substantially semicircular pass face whose continuity is interrupted throughout an arc of about 10 at a point substantially 50 from the valley of its shaping pass to form a recess for the initial reception of the edges of skelp whose sides are initially engaged by the rolls solely at points spaced from its edges. a

4. In an apparatus for making welded cylindrical tubing from heated flat metal skelp, a pair of cooperating rolls forming a substantially circular skelp-shaping pass, each roll being provided with a substantially semicircular pass 'face extending from the valley of its shaping pass to a terminal point about 50 therefrom, whereby skelp is initially engaged by the terminal portions of the roll i'aces solely at points spaced from its edges.

5. The method of progressively shaping heated fiat metal skelp to cylindrical shape for forming welded tubing, comprising initially engaging the sides 01' the skelp solely at points spaced from A its edges while passing the skelp through a pair of cooperating shaping rolls.

6. The method oi! progressively shaping heated flat metal skelp to cylindrical shape for forming welded tubing, comprising initially applying opposed pressures to the exterior face of the skelp solely at points spaced from its edges while passing the skelp through a pair of cooperating shap-' ing rolls.

HARRY J. KLUG. 

